U.S. Pat. No. 7,495,300 B2 discloses a gas-sensing semiconductor device on silicon, comprising a resistive heater made of tungsten embedded in a thin silicon oxide layer that is formed over a recess of the silicon substrate. The device can be monolithically integrated with a circuitry using a CMOS process.
U.S. Pat. No. 7,659,612 B2 discloses semiconductor components comprising through wire interconnects, which are partially encapsulated by a polymer layer and include redistribution conductors and pads electrically connected with substrate contacts. A method for fabricating the components can include a film assisted molding process for forming the polymer layer on the wafer level. Following the film assisted molding process the components are singulated. The semiconductor components can be used to fabricate stacked systems.
TW 1290358 B discloses a packaging for a micro gas sensor, which is mounted in a receptacle of a carrier and is provided with electric connections. The receptacle is closed by a filter component, which is fixed to the carrier above the sensor and comprises a structure net and a thin film.
KR 101034647 B1 describes a wafer-level packaging for a gas sensor. A substrate comprising cavities containing sensors and support units is covered with a further substrate, which is provided with a cavity and an infrared filter. The substrates are bonded by means of a metal solder layer.
US 2012/0056312 A1 describes a production method for a stack of semiconductor wafers comprising through silicon vias and a plurality of dies mounted in cavities between the vias. An encapsulant is deposited over the dies. Interconnect structures are formed above the encapsulant and are electrically connected to the vias. When the wafers are provided with the encapsulant and the interconnect structures, they are mounted on top of each other.
US 2007/0045515 A1 discloses microelectronic imaging devices having integrated circuits and image sensors on opposite sides of a substrate, which is provided with through-substrate vias. Standoffs formed from a cover material support a transmissive element including glass, which is attached to the standoffs by attachment elements including adhesive layers and protects a microlens array and other features from contamination. The cover material can include a photoresist or another selectively removable substance.
US 2009/0256216 A1 discloses a wafer-level chip scale package of a sensor with a substrate comprising ICs, through-silicon vias and a protective encapsulant layer covering the top surface. Above a cavity accommodating the sensor, a cap is arranged either flush with the encapsulant layer or partially covered by the encapsulant layer.
US 2006/0154401 A1 discloses gas-sensing semiconducting devices including a gas-sensitive layer and a heater arranged in the vicinity of the gas-sensitive layer.
GB 2303710 A discloses a gas sensor with a gas-permeable membrane formed from polytetrafluoroethylene.
JP 2001-337063 A discloses a gas sensor inserted in a recessed part of a housing with bumps of the gas sensing part turned downward. Leads are connected by heating the bumps while the sensor main body is lowered towards the leads.
EP 1775259 A1 discloses a wafer level package for devices that may include two different sensors, in particular a pressure sensor and an accelerometer.
US 2010/0230766 A1 discloses a sensor device comprising an encapsulating mold material with polytetrafluoroethylene used as a coating material.